1. Field of the Invention
This invention relates to a microscope illumination apparatus which has at least three kinds of light sources, each of a different emission wavelength region and a different figure of a light-emitting section, and is capable of supplying light of a desired wavelength to a microscope body in accordance with a desired fluorescence observation.
2. Description of Related Art
As this type of conventional microscope illumination apparatus, the light source section of a fluorescence microscope set forth, for example, in Japanese Patent Kokai No. 2005-10296 is available.
FIG. 1 shows essential parts of one structural example of the microscope illumination apparatus set forth in Kokai No. 2005-10296.
The microscope illumination apparatus of FIG. 1 has three light sources of different wavelength regions (an LED unit including a red LD 151, a green LED 152, and a blue LED 153); a collimator lens unit 154; a mirror 155; a dichroic mirror 156; a lens 157; and an optical fiber 158. Light emitted from the individual light sources 151-153 is introduced into one optical path through the mirror 155 and the dichroic mirror 156 and is rendered incident on the entrance end face of the optical fiber 158 through the lens 157. In this case, in light sources in which emitted rays are liable to be diffused (the green LED 152 and the blue LED 153), the emitted rays are converted into parallel rays through the collimator lens unit 154.
The light emerging from the optical fiber 158 is supplied to the microscope body through a projection means, not shown in the figure, such as a collimator lens.
In the light source such as the LED or LD, the figure and size of the light-emitting section vary with the emission wavelength region.
However, when the figure and size of the light-emitting section vary, the size of the image of the light source formed on the entrance end face of the optical fiber and an angle of incidence of a ray vary with the light source. In the optical fiber, the minimum angle at which incident light is totally reflected (a critical angle) varies with an incident wavelength.